Servo-sector arrangement over several data arcs for a rotational head data recording and retrieving system

ABSTRACT

This invention discloses a plurality of substantially parallel data arcs disposed on a flat data storage medium. The data arcs include at least two linearly aligned servo-data fields disposed in an inner data arc and an outer data arc with an inter-arc distance. The servo data field disposed on the outer data arc is disposed with an offset from an identical radial-angle position projected from a radial center to the servo data field of the inner data arc. The offset is substantially proportional to the inter-arc distance and substantially proportional to SIN (θ) where θ is an angle between the identical radial-angle position and a linear-alignment direction between the two linearly aligned servo-data fields. Furthermore, the servo-data field on the outer data arc is disposed at a location with the offset from the identical radial-angle position in a direction toward a smaller radial angle projected from the radial center to the servo data field of the inner data arc.

This Application is a Continuation-in-Part Application (CIP) of apreviously filed Provisional Application 60/081,257 filed on Apr. 9,1998 and a Formal Application 09/289,427 now U.S. Pat. No. 6,417,980,filed on Apr. 9, 1999, by one of a common inventors of this PatentApplication.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to systems and method for reading datafrom and writing data to data storage medium by employing the magneticor optical recording technology. More particularly, this invention isrelated to a new servo data arrangement provided on data tracks on aplanar medium surface for high accuracy positioning of a rotating head.

2. Description of the Prior Art

There are difficulties when conventional method and arrangement areemployed for writing servo data on several data arcs for providingservo-control information to control the placement of pickup head ondesignated data arcs on a rotational-head data recording system. Unlikea conventional data recording and retrieving system, the pickup head ofa rotational-head system is controlled to rotate over several data arcs.In contrast, in a conventional data recording and retrieving system, thepickup head is controlled to move over a linear direction transversal tothe circular data tracks on the recording medium. For a rotational headdata recording system, the relative motions between the pickup head andthe data recording arcs are different from that of a conventional datarecording system. Because of these differences in relative motions, theconventional methods of arranging servo-data sectors on each data trackfor recording the servo data are no longer useful. In the meantime, thepickup head must be controlled to accurately position over thedesignated locations on designated data arcs for performing the datarecording and retrieving processes. For high density data recordingsystem, precise placement is becoming even more important. It becomescritically important that the servo data recorded on servo-data sectorsare employed to eliminate errors caused by dimensional variations,misalignment of mechanical parts, and other performance variations ofelectrical and optical components of the data recording system.

The rotational head data recording and retrieving system is disclosed inthe invention is to resolve the difficulties of the conventionaltechnology. In conventional data storage systems, the reading andwriting of data are performed on concentric circular data tracks. Theconcentric data track configuration often presents a problem that thedata-bit density varies between the outer tracks and the inner tracks.The variable bit density in data storage is due to a geometric factorthat the outer data tracks are much longer in length that the innertracks. A common practice is to form the inner tracks with a capacity tostore the data bit at a higher bit density. A more complicate servocontrol system implemented with more complex signal-processingalgorithms is required due to the variations of data storage densitybetween different data tracks. Additionally, by varying the data storagedensity from the inner tracks toward the outside tracks, the datatransfer rate is also changed in accessing data from the inner tracksthen outside tracks. Such variation may also cause difficulties andcomplications in processing the data. Higher error rates may incur dueto these variations between the inner tracks and the outer tracks.

Therefore, a need still exists for an improved data-card drive systemwith novel sector arrangement for writing servo-data in different dataarcs to overcome the aforementioned difficulties encountered in theprior art. Specifically, the storage card drive system shall provide auniform density for data storage and a data-card drive system withproperly servo-sector arrangement to access the data-storage card.Furthermore, it would be desirable that this system is portable and isalso provided with several standardized sizes for processingstandardized data-storage cards.

SUMMARY OF THE PRESENT INVENTION

Therefore, an object of the present invention is to provide a datastorage-card drive system with a pickup head moving above thedata-storage card in rotational movement. The data read-write functionsare enabled only for arc-segments of the rotational movement guided byservo data written to servo sectors on the data arc with proper offsets.Also, the data tracks are arranged as plurality of parallel arcs, e.g.,half-circles, and the servo data sectors are arranged to have offsetbetween different arcs to overcome the aforementioned difficulties andlimitations encountered in the prior art.

Specifically, it is an object of the present invention to provide adata-storage card drive system with a pickup head driven by a motor,e.g., a brushless motor, to rotate over the data-storage card with therotation axis perpendicular to the card surface. The motor is mounted ona carriage for making horizontal movement along a longitudinal directionof the data card. The position of the pickup head is thenservo-controlled with inter-arc offset arrangement of servo-data sectorsfor moving the carriage and the motor while the data storage card eitherstays at a fixed position or only pickup head is rotating and the cardis making horizontal linear movements.

Another object of the present invention is to provide a data-storagecard drive system for performing the data access tasks over a datastorage medium surface, which has uniform data storage density. A newconfiguration of data-tracks formed as parallel arc or arc-segments,e.g., semi-circular data track, is implemented such that all data trackshave substantially the same length for data storage and the data bitsare stored with uniform density.

Briefly, in a preferred embodiment, the present invention discloses aplurality of substantially parallel data arcs disposed on a flat datastorage medium. The data arcs include at least two linearly alignedservo-data fields disposed in an inner data arc and an outer data arcwith an inter-arc distance. The servo data field disposed on the outerdata arc is disposed with an offset from an identical radial-angleposition projected from a radial center to the servo data field of theinner data arc. The offset is substantially proportional to theinter-arc distance and substantially proportional to SIN (θ) where θ isan angle between the identical radial-angle position and alinear-alignment direction between the two linearly aligned servo-datafields. Furthermore, the servo-data field on the outer data arc isdisposed at a location with the offset from the identical radial-angleposition in a direction toward a smaller radial angle projected from theradial center to the servo data field of the inner data arc.

These and other objects and advantages of the present invention will nodoubt become obvious to those of ordinary skill in the art after havingread the following detailed description of the preferred embodimentwhich is illustrated in the various drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B shows a cross sectional view and a top view respectivelyof a data card drive system of this invention;

FIGS. 1C and 1D are cross sectional views for showing the details of themotor rack mounting and the head loading/unloading assembly;

FIG. 1E shows a perspective view of the pickup head and the wireswinding configuration serving as read/write data signal transformer;

FIGS. 1F and 1G show the top view and cross sectional view respectivelyof a magnetic or optical servo writer of this invention;

FIGS. 2A to 2C are respectively a top view, a cross sectional view and abottom view of a data storage card with data tracks formed for storingbits with uniform density in each of these data tracks;

FIGS. 2D to 2Q show the top views of the data storage card of thisinvention where the data tracks can be arranged in arc-segments ofdifferent shapes, sizes, and facing different directions;

FIGS. 3A and 3B are a perspective view and a cross sectional viewrespectively of a data card storage box;

FIG. 4 is a functional block diagram of a subsystem of this inventionincludes a data card drive device of FIGS. 1A to 1C for reading/writingdata storage card of FIGS. 2A to 2C;

FIGS. 5A and 5B show the data tracks on a magnetic or optical data cardwith data tracks for writing servo data thereon;

FIG. 5C shows an exemplary pattern of servo data written onto a datatrack;

FIG. 5D shows the position indexes for servo control;

FIG. 5E is a functional block diagram to illustrate the control logicimplementation of a servo write of this invention;

FIG. 6 is a top view of a data medium surface with multiplesubstantially parallel data arcs with horizontal lines representingaligned positions at different data arcs;

FIG. 6A shows the movement of a pickup head disposed above concentrictracks for illustrating the radial angle projected from the centerpoint;

FIG. 7 is a top view of a data medium surface with multiplesubstantially parallel data arcs showing aligned positions between twodifferent data arcs having an inter-arc offset depending on theinter-arc distance and a radial angle; and

FIG. 8 is a top view of a data medium surface with multiplesubstantially parallel data arcs showing different servo-data fieldalignment zones.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1A and 1B show a cross sectional view and a top view respectivelyof a data-card drive 100 of the present invention. The data-card drive100 can be configured for reading and writing data-cards of differentsizes, e.g., a PCMCIA type card or common credit card size. Thedata-card can also be of different shapes such as a square, arectangular, a circular disk, or a card with straight and parabolicedges or different types of arc-edges. The data-card drive 100 includesa motor 110, e.g., a DC brushless motor. The motor 110 is provided tooperate at a low speed to conserve battery power, at high speeds toachieve fast data access time. The motor 110 is further provided tofunction at two different modes, i.e., a sleep mode when not beingdeployed, and a wake up mode for normal data access operations. Themotor 110 is mounted on a carriage 115 with a pickup head assemblymounted to the motor rotating shaft assembly. Half of a magnetictransformer, 120-1 which can either being a ring type, a round-disktype, or other geometrical shapes, is mounted onto the motor rotatingshaft assembly, the other half of the magnetic transformer 120-2 ofsimilar configuration is mounted to the fixed part of motor assembly.Signal wires 130 from head are soldered onto the rotating half of thetransformer 120-1 with the soldering pad 125, that can also be a springpressed connection, for transmitting the read/write signals via themagnetic transformer 120. The magnetic transformer 120-1 and thesoldering pad 125 are covered by a magnetic flux shield plate 135 forshielding the magnetic flux generated by the magnetic transformer toprevent DC erase of data. A ground spring 140 is applied to perform thefunction of dissipating electric static discharge. Optionally, abrake-magnet 145 is provided to fix the “parking” position of the motor110 in the sleep or power off mode during the time when there is no dataaccess activities.

A read/write head 150 is mounted via an extended head-arm 152 to thebrushless motor 110 via a head-arm mounting assembly mounting holes 155to the head carriage 115. A head loading/unloading arm 160 is mounted onthe base-plate 170. The loading/unloading arm 160 presses to thehead-arm 152 at the unload position at a drive-device power-off mode.The loading/unloading arm 160 is removed from the head-arm 152 when adata card 180 is loaded and the power for the drive device is turned on.

In order to assist a smooth loading of the data card 180 into the drivedevice 100, a card guide plate 185 is provided. The data-card drivesystem 100 further includes one or several data card pins 190 to engageand fix the position of the data card 180 when the data card 180 reachesa designated operational position. The data card pins 190 increases thecompatibility and interchangeability of different types of data cardsfor data access operations using this data card drive system 100. Thedrive system 100 further includes an on/off switch 195, which is turnedon when the data card 180 reaches its final position.

The brushless motor 110 is mounted onto a motor-rack mount 200 with arack 205 and a pinion 210. A step motor 220 is employed to control thelinear movement of the motor 110 or the movement of the data card 180.The drive device 100 further includes a LCD display 230 to indicate thetrack position of the head 150 in reading or writing of data onto thedata card 180. Mounted on the base plate 170 is printed circuit board240, which supports a track locator switch 245. The printed circuitboard 240 further supports various kinds of circuits for performing thefunctions of control and data access. These circuits includes headtracking circuit 250, IC preamplifier 255, head loading/unloadingcircuits, disable/enable read-write function circuit, servo controlintegrated circuit (IC), motor control IC, data separator IC, ADIinterface IC, USB interface IC, PCMCIA interface IC, USB connector,PCMCIA connector, and other circuits required for controlling andoperating the data card drive system. FIGS. 1C and 1D are crosssectional views for showing the details of the rack 205, the pinion 210,and the head loading and unloading assembly 160 to lift the head whenthe drive device 100 is turned off. A head arm lifter 103 has a wiretype hook 103A positioned above the pickup head arm 152. The sliding ofthe head arm lifter 103 with the wire type hook 103A along the motorshaft assembly can lift or lower the pickup head arm 152 and in turnlift or lower the pickup head 150. The pickup head arm 152 is rotatingwith the motor shaft and the pickup head 150. Regardless of where thepickup head 150 when the rotational movement stops, the arm 152 canalways engage into the head lifter 103 slot and sliding the head lifter103 along the motor shaft.

The drive device 100 as described above is also provided with an optionto perform the functions of a servo writer. A novel servo writer isdisclosed in this invention which can be manufactured with simplifiedmanufacturing processes. The servo writer includes a storage cardloading assembly that is structure similarly to a card guide 185 of thedevice 100. The storage card can be inserted horizontally inserted fordirect contact with the pickup head 150. Or, depending on specificapplication, the data storage card can be inserted from a vertical slotopening and then flip over for contact with the pickup head. In writingthe servo data, the pickup head 150 is rotating along different datatracks. The pickup head is moved to different tracks during theoperation of writing servo data by either moving the head/motor assemblymounted on the shaft or by keeping the head/motor assembly stationarywhile horizontally moving the data storage card. The magnetictransformer is employed in writing the servo data onto different datatracks where the cables are arranged without being twisted when thepickup head is making rotational movement.

FIGS. 1F and 1G are a top view and a cross sectional view of a preferredembodiment of a data-card servo writer system 100′, which has a clockhead 105 connected to a clock disk 107. The clock disk 107 is disposedbelow the magnetic or optical data card 180 and de-coupled from the datacard 180. The motor drives the pickup head 150 also drives the clockdisk 107. The clock disk can be rotated while the clock head 105 isfixed and stationary and mounted on the frame assembly of the servowriter system 100′. The clock head 105 is employed to write clocksignals, e.g., a binary bit 1 for the whole cycle. All of the data bitson the entire data track of the clock track are binary bit “1”. Then, apulse is stopped to write a binary bit “0” to provide that “0” as indexwhile using all the bit “1” for timing to format the card. Read andwrite signals of the clock head 105 is transmitted through wires to theclock disk 107 formed on a printed circuit board. The clock head 105 isemployed to write the clock signals onto the magnetic or optical clockdisk and to read back the signals. The clock signals read back from themagnetic or optical clock disk are used as timing signals to format thecard to include the servo patterns to be further described below. Oncethe magnetic or optical data-card 180 is formatted by the servo-writersystem 100′, it is ready for data read/write operations by applying aregular magnetic or optical data-card drive system as that shown inFIGS. 1A to 1E. The formatted sectors on the magnetic or opticaldata-card 180 are also write-protected to prevent incidental writingover these segments.

According to FIGS. 1A, 1B, 1C and 1D and above descriptions, the presentinvention discloses a data-card drive system 100 the present inventionincludes a magnetic or optical data-card drive system. The drive systemincludes a magnetic or optical pickup head for rotationally moving overand accessing data stored in the magnetic or optical data-card. In apreferred embodiment, the magnetic or optical pickup head is providedfor reading data from and writing data to the magnetic or optical datacard. In another preferred embodiment, the magnetic or optical pickuphead is provided for accessing data over substantially one-half of therotational movement. In another preferred embodiment, the magnetic oroptical pickup head is provided for accessing data over severalarc-segments during the rotational movement. In another preferredembodiment, the magnetic or optical pickup head is provided for rotatingin a single rotational direction. In another preferred embodiment, themagnetic or optical pickup head is provided for rotating in clockwiseand counterclockwise directions. In another preferred embodiment, themagnetic or optical pickup head is provided for rotating over arcsegment having radius smaller than half-width of the magnetic or opticaldata card. In another preferred embodiment, the magnetic or opticalpickup head is provided for rotating over an arc segment having a radiusgreater than half-width of the magnetic or optical data card. In anotherpreferred embodiment, the magnetic or optical pickup head is provided asa removable and replaceable module. In another preferred embodiment, themagnetic or optical pickup head is provided for accessing data bycontacting the magnetic optical data card. In another preferredembodiment, the magnetic or optical pickup head is provided foraccessing data by rotating at a distance above the magnetic or opticaldata card. In another preferred embodiment, the magnetic or opticaldata-card drive system of further includes a motor that has a rotatingshaft for mounting and rotating the magnetic or optical pickup head. Inanother preferred embodiment, the magnetic or optical pickup headfurther includes a data signal transformer for transforming a datasignal through data signal induced changes of magnetic flux.

FIG. 1E is a perspective view of an alternate configuration of a datasignal transformer 120′. The data signal wires 130-1 connected to thepickup head 150′ supported on the arm 152′ for the pickup head 150′ arefirst winding around an inner signal transforming cylinder 122′, whichrotates with the rotation shaft or the motor 110′. A stationary hollowpipe 124′ is placed around the inner signal-transforming cylinder 122′.A set of signal transforming wires wrap around this stationary hollowpipe 124′. For read/write data, an electric signal representing a binarybit can be transferred from a pickup head 150′ through the wires 135′ tothe wires wrapping around the inner signal-transforming cylinder 122′.The electric signals, typically an electric pulse, transferred to thewires around the inner cylinder 122′ can be detected with variations ofelectromagnetic field by a set of wires wrapping around the stationaryhollow pipe 124′. Similarly, the data signal for the pickup head 150′can also be provided to the wires wrapping around the stationary hollowpipe 124′ as electric pulses and detected by the wires wrapping aroundthe inner signal transforming cylinder 122′ for transfer to the pickuphead 150′. The wires around the inner and outer cylindrical pipesfunction as inductive coils serving the function of data signaltransformation.

FIGS. 2A to 2C are respectively a top view, a cross sectional view, anda bottom view of a data card 180 of the present invention. The data card180 is formed on a substrate plate 250. The substrate-plate 250 formagnetic recording is compressed of non-magnetizable materials with aflat surface, e.g., a plastic or glass substrate plate. For magneticrecording, a magnetizable material can also be employed to form thesubstrate plate 250. The substrate plate 250 is then coated with a thinlayer of recording medium on one side or both sides. For magneticrecording, the coating are formed by magnetic particles coated onone-side or both sides of the substrate plate 250. The magnetic coatingcan be directly on the surface of the substrate plate 250 or on a Mylartype of material with adhesive layer for attaching to the substrateplate 250. For magnetic recording the recording medium layer can beformed by a process similar to that of a magnetic compact-disk (CD),CDR, LD, or digital video display (DVD) disks. The data card 180 can beformed with standardized sizes, e.g., PCMCIA standard sizes or standardcredit card sizes, and has round or elongated holes 260 for fixing thecard at pre-designated positions to initialize a data access operation.The holes 260 are fitted to the pins 190 to provide the self-centeringand locking functions. The data storage card 280 can therefore berepeatedly placed at a pre-designated position with reliable array. Thedata card 180 is provided with a plurality of data tracks 270 forstoring data bit on each track. Each of these data tracks is formed assubstantially an arc or arc-segment track. The data tracks 270 aresubstantially of a same length and are substantially parallel to eachother. The data tracks 270 are formatted to include multiple sectors.One or several of these sectors can be flexibly employed to provideservo data for the purpose of identifying track locations to enhancesector seeking during a data-access operation. The servo-data areprovided in sectors near both ends of the arc or arc-segments datatracks 270 as shown in FIG. 2A. For the purpose of more preciselypositioning the data card 180 in a drive device, a notch 275 is formednear the inner end of the data card 180. With the notch 275, the datacard 180 is more conveniently placed into the drive device fitted to theinitial card position ready for operation relative to the position ofthe pickup head 150. The data card 180 is then covered by a protectivecoating 280 preventing damages from exposure to water, dust and otherforeign particles introduced through the daily operational environment.The data card 180 is then stored in a data card envelope 290 for storageand shipment. The data storage tracks of the data card may contain userapplication and system configuration data. The recorded data can beupdated in the field. Application system can either encrypt or decryptthe recorded data. Application system can also change the configurationsuch as set and reset the write protection, the password and otherfeatures related to the data-access operations.

FIGS. 2D to 2Q are top views of the data storage card 180 for showingdifferent configuration of the data tracks 270. The data tracks 270-1can be parallel arcs facing opposite directions on either side of thedata card 180 as shown in FIG. 2D. Alternately, each of the data tracks270-1 as parallel arc as that shown in FIG. 2D can be partitioned into aplurality of arc-segment 270-2 as that shown in FIG. 2E. In a similarmanner, the data tracks can be parallel arcs 270-3 formed over theentire data card area as that shown in FIG. 2F. Furthermore, each of theparallel arcs 270-3 of FIG. 2F can also be partitioned into a pluralityof arc segments 270-4 as that shown in FIG. 2G.

According to FIGS. 1 to 2, this invention discloses a magnetic oroptical data-storage card. The magnetic or optical data-storage cardincludes a magnetic or optical data-storage medium layer supported onthe card. The data-storage medium layer includes a plurality of datastorage tracks for storing data therein. Each of the tracks comprisingat least an arc-segment wherein each of the data storage track beingsubstantially parallel to a neighboring track. In a preferredembodiment, each of the arc-segments are substantially of a same segmentlength. In a preferred embodiment, the data-storage tracks furtherstoring servo control data. In a preferred embodiment, the data-storagetracks further storing the servo-control data at a substantially samerelative position on the data-storage tracks. In another preferredembodiment, the data-storage tracks further storing the servo-controldata near edges of the data-storage card on the data-storage tracks. Inanother preferred embodiment, each of the data-storage tracks issubstantially a semicircular arc-segment. In another preferredembodiment, each of the data-storage tracks includes several arcsegments. In another preferred embodiment, the magnetic or opticaldata-storage card further includes self-positioning guiding means forguiding the card to a loading position when inserted into a data carddrive device. In another preferred embodiment, the magnetic or opticaldata storage card having a first side and a second side and thedata-storage tracks are disposed on the first and second sides. Inanother preferred embodiment, the magnetic or optical data storagefurther includes a card jacket for storing the data storage card.

Furthermore, this invention provides a new method for storing data in amagnetic or optical data-storage card. The method includes the steps ofa) providing a magnetic or optical data-storage medium layer supportedon the data-storage card. And, b) forming in the data-storage mediumlayer a plurality of data storage tracks for storing data therein byforming each of the tracks to include at least an arc-segment and eachof the data storage tracks substantially parallel to a neighboringtrack. In a preferred embodiment, the step of forming the data-storagetracks as arc segments is a step of forming each of the arc segmentssubstantially of a same segment length. In another preferred embodiment,the method further includes a step of storing servo control data in thedata-storage tracks. In another preferred embodiment, the step ofstoring the servo-control data is a step of storing the servo-controldata at a substantially same relative position on the data-storagetracks. In another preferred embodiment, the step of storing theservo-control data is a step of storing the servo-control data nearedges of the data-storage card on the data-storage tracks. In anotherpreferred embodiment, the step of forming the data-storage to include atleast an arc segment is a step of forming each of the data-storagetracks substantially as a semicircular arc-segment. In another preferredembodiment, the step of forming the data-storage to include at least anarc segment is a step of forming each of the data-storage tracks toinclude several arc segments. In another preferred embodiment, themethod further includes a step of providing a self-positioning guidingmeans for guiding the magnetic or optical data-storage card to a loadingposition when inserted into a data card drive device drive. In anotherpreferred embodiment, the step of providing a magnetic or opticaldata-storage medium layer supported on the card is a step of providingthe magnetic or optical data storage card to include a first side and asecond side. And, the step of forming in the data-storage medium layer aplurality of data storage tracks is a step of forming the data-storagetracks on the first and second sides. In another preferred embodiment,the method further includes a step of providing a card jacket forstoring the data storage card.

FIGS. 3A and 3B are a perspective view and a side view of a data cardstorage rack 295 for storing a plurality of data card 180 therein. Thedata card storage rack 295 as shown can be formed as partitioned storagebox with each compartment ready to receive one data card 180. The datacard storage rack 295 can function as a portable digital camera album ora backup data store for long term data storage.

FIG. 4 shows a subsystem 300 of this invention that includes a data carddrive device 310 identical with the drive device 100 described aboveaccording to FIGS. 1A to 1C. The disk drive device 310 performs the dataaccess tasks on a data storage card 320 identical to the data card 180described above according to FIGS. 2A to 2C. The subsystem 300 furtherincludes a local memory 330, which can be a DRAM or SRAM memory deviceconnected to the disk drive device 310. The data stored in data card 320can be first downloaded to the memory device 330 through a data bus fordata storage. The subsystem 300 further includes a function controlpanel 340 to allow a user to control the subsystem startup, shutdown,save, update, and duplication of the data stored in the card. Thesubsystem 300 is further provided with a connection terminal 350 forconnection to a personal computer, a printer, a scanner or otherperipheral devices for operation together with the drive devicesubsystem 300. A power supply 360 is employed and connected to thesubsystem 300 to provide power necessary for operating the drive device310, the memory 340 and the control panel 330.

Referring to FIGS. 5A to 5C for examples to illustrate the servo signalpatterns written onto the arc segments of the data-storage tracks on adata storage card. FIG. 5A shows the data storage tracks as arcsegments, which may or may not be circular arcs. The servo writer mustwrite servo signals on these data-tracks. Referring to FIG. 5B, thesurface area of the magnetic or optical data-storage card is dividedinto zones A to F according to clockwise direction. The servo writershould be disabled for Zones A, B, D, and E since these zones are notpart of the data tracks. The servo writer must also be disabled in zoneE because the servo data may be overlapped and create confusions in theprocess of pickup head location and track determinations. It is obviousthe conventional servo writer and control mechanisms can no longer beemployed for the magnetic or optical data card drive system of thisinvention.

As shown in FIG. 5A, the length of the data tracks depends on the sizeand dimensions of the data card. Each data track is divided into Nsegments and each segment is provided to contain pre-defined servo data,prerecorded data and/or definitions of area for data records. FIG. 5C isan example of the data arrangements across the tracks of such segments.The total number of data tracks N is determined by the requirements ofthe accuracy of the mechanical and electrical responses. The servo datashown in FIG. 5C can provide the track profile, the location of thetrack and the relative location of signal pickup head to a data trackalong a track.

Referring to the details of data arrangement shown in FIG. 5C, thesignals generated from data bit-patterns A and B are for positiondetermination. Each data track has a half data slots provided for A andhalf of the slots provided for B. The balance of A and B detected by thepickup head and the track location determination circuits provideindications that the pickup head is traveling in the center of the datatrack. Table 1 shows the data sample employed for providing servo datafor track and location determinations as the pickup head is travelingover the surface of the magnetic or optical data storage card.

TABLE 1 Example of Partial Servo Segment Data SYNC 1010101010101010 ADM1000000010000001 ST IDX 11 for First Segment 00 for other segments EDIDX11 for last segment 00 for other segments A 0000001100000000 B0000000000000011

Referring to FIG. 5D, since the data track can only be arc-segments asthat shown FIG. 5A, the servo writer must start and stop to layoutpatterns at pre-determined locations. An index is used as a referencepoint at a fixed location on the magnetic or optical data-storage card.The starting point SX and the stopping position EX of the servo data arederived from the reference point IX as shown in FIG. 5D. A servo controlcircuit is employed to enable and disable the pattern layout process andto move the magnetic or optical pickup head and the flat data-storagemedium, i.e., the magnetic or optical data storage card by using thefeedback by detecting these three indices. An exemplary functional blockdiagram for implementing the control logic in the servo control circuitis shown in FIG. 5E.

According to FIGS. 5A to 5E, this invention discloses a magnetic oroptical servo writer. The magnetic or optical servo writer includes amagnetic or optical pickup head for rotationally moving over and writingservo data in a magnetic or optical flat data-storage medium. Themagnetic or optical servo writer further includes a clock head forproviding clock signals to the pickup head and to write clock signals inthe clock disk. The magnetic or optical pickup head is provided forwriting SYNC data for synchronization of read channel, and ADM data forproviding address mark for indicating data-types following the ADM data.The magnetic or optical pickup head is provided for writing ST IDX datafor indicating a first valid data segment, ED IDX data for indicating alast valid data segment, and GRAY CODE data for indicating a headnumber, a sector number, and a track number. Furthermore, the magneticor optical pickup head is provided for writing SERVO POS data forindicating a relative position of signal head to a data track, DATA &GAP data for indicating an area for containing pre-recorded data. In apreferred embodiment, the magnetic or optical pickup head is providedfor writing index data for indicating a valid data track segment.

According to the functional block diagram of FIG. 5E and FIGS. 1F and1G, a magnetic or optical servo writer is disclosed in this invention.The magnetic or optical servo writer includes a magnetic or opticalpickup head for rotationally moving over and writing servo data in amagnetic or optical flat data-storage medium. The magnetic or opticalservo writer further includes a clock head for providing clock signalsto the clock head and to write clock signals in the magnetic or opticalclock disk. The magnetic or optical servo writer further includes acontrol circuit for controlling the magnetic or optical pickup head forwriting the servo data on the magnetic or optical flat data-storagemedium. The magnetic or optical servo writer further includes a servopattern layout circuit for controlling the magnetic or optical pickuphead for writing the servo data on the magnetic or optical flatdata-storage medium with predefined servo patterns. The magnetic oroptical servo writer further includes a derived index control circuitfor deriving indices from a fixed index provided on the magnetic oroptical flat data-storage medium. The magnetic or optical servo writerfurther includes a fixed index and clock track circuit for providing afix index and a clock signal for controlling the magnetic or opticalpickup head for writing the servo data on the magnetic or optical flatdata-storage medium. The magnetic or optical servo writer furtherincludes a head move circuit for controlling a movement of the magneticor optical pickup head for writing the servo data on the magnetic oroptical flat data-storage medium. The magnetic or optical servo writerfurther includes a medium movement circuit for controlling a linearmovement of the magnetic or optical flat data-storage medium for writingthe servo data on the magnetic or optical flat data-storage medium.

Referring to FIG. 6 for multiple parallel data arcs represented by K1,K2, . . . , Kn where each data arc is formed at a distance D from aneighboring data arc. Two horizontal lines A1, A2, are drawn along anX-axis to show that a horizontal alignment between these parallel arcsare different from the alignment configuration of a conventionalcircular data tracks. According to conventional method of alignment, thealigned positions are defined by segments disposed on different trackshaving a same radial angle as that shown in FIG. 6A naturally followinga lateral movement of a pickup head over a rotational storage medium.When compared to conventional radial-angle alignment, as that shown inFIG. 7, an offset S is shown when the pickup head is moving from onetrack to another track. The aligned position G2 on an outer arc K2relative to the position G1 on arc K1, is now disposed at a distance Sfrom conventional identical angular position projected from the radialcenter point through G1. The offset S is represented by S=M Sin(θ) whereM is the distance between arc K1 and K2, and T is the radial angle of G1when projected from a radial center of the arcs K1 and K2.

According to FIG. 7, this invention discloses a plurality ofsubstantially parallel data arcs, e.g., K1 and K2, disposed on a flatdata storage medium substantially perpendicular to an axis-X. These dataarcs includes at least two parallel-to-X-axis aligned servo-data fieldsG1 and G2 disposed in an inner data arc K1 and an outer data arc K2 K1and K2 have an inter-arc distance and the servo data field disposed onthe outer data arc K2 is disposed with an offset from an identicalradial-angle position relative to said X-axis projected from a radialcenter to the servo data field of the inner data arc. The offset isproportional to the inter-arc distance M. The offset is alsoproportional to SIN (θ) where θ is the radial angle relative to saidX-axis. The servo-data field G2 on the outer data arc K2 is disposed ata location with the offset from the identical radial-angle position in adirection toward a smaller radial angle projected from the radicalcenter to the servo data field G1 of the inner data arc K1. With theservo data-field G1 as a reference, the servo data-filed G2 at the outerarc K2 must be adjusted with this offset in order to align with thedata-filed G1 to properly provide servo feedback.

According to the above descriptions, the offset S between the servodata-fields on different data tacks grows larger with θ and inter-arcdistance, i.e., the inter-arc distance M. The higher the M the largerthe S, the larger θ the larger S. There are multiple track andmultiplier servo fields along a track, referring to FIG. 8, the fartheraway the servo data-field is located from the center reference line axisX, the larger the offset. The farther away from the track 0, the largerthe offset. Referring to FIG. 6 again, a group of tracks K1, K2, . . .Kn is mapped. Using track K1 as a starting track, servo fields of K2,K2, . . . , Kn must be aligned to the previous track by adding an offsetrelated to θ and track distance from K1. The offset is accumulative. Attrack farther away of K1, the sum of offset can cause the track field toexceed the allowed region confined by line A1 and A2. A new track groupzone can be established with a new starting track similar to K1 to Knagain. FIG. 8 shows such example arrangement. There are ten track zones.Five zones each at opposite sides. Zone 1 has track number 0 to 153sector 0 to 41, the opposite size zone 6 has track number 0 to 153sector 42 to 81. Zone 2 has track number 154 to 307 sector 0 to 41, theopposite size zone 6 has track number 154 to 307 sector 42 to 81, etc.For zone 1 and zone 6, the accumulated offset increases from track 0 totrack 153. The offset at track 154 in zone 2 and zone 7 is reset to zeroand accumulated to increase to track 307. The offset at track 308 inzone 3 and zone 8 is reset to zero and accumulated to increase to track461. The offset at track 462 in zone 4 and zone 9 is reset to zero andaccumulated to increase to track 615. The offset at track 616 in zone 5and zone 10 is reset to zero and accumulated to increase to track 769.

Therefore, the present invention discloses a data storage-card drivesystem with a pickup head moving above a data-storage card in rotationmovement. The data read-write functions are enabled only for an arcsegment, e.g., half-circle, or several arc segments of the rotationalmovement. The data tracks are arranged as plurality of parallel arcs,e.g., half-circles, or arc-segments with uniform data bit storagedensity. Specifically, a pickup head is provided, which is driven by abrushless motor to rotate over the data-storage card. The motor ismounted on a carriage for making horizontal movement along alongitudinal direction of the data card. The position of the pickup headis then servo-controlled by moving the carriage and the brushless motorwhile the data storage card either stays at a fixed position or makingonly forward-backward movements. The difficulties and limitationsencountered in the prior art due to a non-uniform data storage densityamong different data tracks are resolved by this invention. Thetechnical difficulties caused by problems in loading/unloading of thepickup head to the recording medium, the transfer of read/write signalbetween the pickup head and the processing circuits, and the selfcentering of the data card in a data card drive device are also resolvedby this invention. Furthermore, the difficulty of positioning andlifting horizontal rotating pickup head parallel to a flat recordingsurface at any intermediate stop location to convert the signal from theflat card to parallel rotating pickup head to process circuit.

Although the present invention has been described in terms of thepresently preferred embodiment, it is to be understood that suchdisclosure is not to be interpreted as limiting. Various alternationsand modifications will not doubt become apparent to those skilled in theart after reading the above disclosure. Accordingly, it is intended thatthe appended claims be interpreted as covering all alternations andmodifications as fall within the true spirit and scope of the invention.

We claim:
 1. A plurality of substantially parallel data arcs disposed ona flat data storage medium comprising: at least two servo-data fieldsdisposed in an inner data arc and an outer data arc with an inter-arcdistance wherein said servo data field disposed on said outer data arcis disposed with an offset from a perpendicular adjacent data fieldlocated at an identical radial-angle position on said outer data arcprojected perpendicularly from a radial center to said servo data fieldof said inner data arc.
 2. The data arcs of claim 1 wherein: said offsetfrom said perpendicular adjacent data field on said outer data arc issubstantially proportional to said inter-arc distance.
 3. The data arcsof claim 1 wherein: said offset from said perpendicular adjacent datafield on said outer data arc is substantially proportional to SIN (θ)where θ is an angle between a first direction projected from said radialcenter perpendicularly to said servo data field disposed on said innerdata arc and a second direction projected from said radial centerperpendicularly to said servo data filed disposed on said outer dataarc.
 4. The data arcs of claim 1 wherein: said servo-data field on saidouter data arc is disposed at a location with said offset from aperpendicular adjacent data field located at said identical radial-angleposition along a direction on said outer data arc toward a smallerradial angle projected perpendicularly from said radial center to saidservo data field of said inner data arc.
 5. A plurality of substantiallyparallel data arcs disposed on a flat data storage medium comprising: acentral perpendicular X-axis substantially perpendicular to saidparallel data arcs near a center point of said parallel data arcs; atleast two parallel-to-X-axis aligned servo-data fields disposed in aninner data arc and an outer data arc with an inter-arc distance whereinsaid servo data field disposed on said outer data arc is disposed withan offset on said outer data arc from a perpendicular adjacent datafield located at an identical radial-angle position projected from aradial center disposed on said X-axis perpendicularly to said servo datafield of said inner data arc; and said offset is substantiallyproportional to said inter-arc distance and substantially proportionalto SIN (θ) where θ is an angle between a first direction projected fromsaid radial center to said servo data field disposed on said inner dataarc and a second direction projected from said radial center to saidservo data filed disposed on said outer data arc.
 6. The data arcs ofclaim 5 wherein: said servo-data field on said outer data arc isdisposed at a location with said offset from a perpendicular adjacentdata field located at said identical radial-angle position along adirection on said outer data arc toward a smaller radial angle projectedfrom said radial center perpendicularly to said servo data field of saidinner data arc.
 7. The data arcs of claim 5 wherein: said parallel dataarcs are divided into multiple zones wherein each zone having areference inner arc; and said servo-data field on said outer data arc ineach of said multiple zones is disposed at a location with said offseton said outer data arc from a perpendicular adjacent data field locatedat said identical radial-angle position along a direction on said outerdata arc toward a smaller radial angle projected perpendicularly fromsaid radial center to said servo data field of said reference inner dataarc.
 8. A method of configuring a plurality of substantially paralleldata arcs on a flat data storage medium comprising: disposingrespectively at least two servo-data fields in an inner data arc and anouter data arc with an inter-arc distance wherein said servo data fielddisposed on said outer data arc is disposed with an offset on said dataarc from a perpendicular adjacent data field located at an identicalradial-angle position projected from a radial center perpendicularly tosaid servo data field of said inner data arc.
 9. The method of claim 8wherein: said step of disposing said servo data fields in an outer dataarc with an offset on said outer data arc is a step of disposing saidservo data-field in said outer data arc with said offset from saidperpendicular adjacent data field substantially proportional to saidinter-arc distance.
 10. The method of claim 8 wherein: said step ofdisposing said servo data fields in an outer data arc with an offset isa step of disposing said servo data-field in said outer data arc withsaid offset from said perpendicular adjacent data field substantiallyproportional to SIN (θ) where θ is an angle between a first directionprojected from said radial center perpendicularly to said servo datafield disposed on said inner data arc and a second direction projectedfrom said radial center perpendicularly to said servo data fileddisposed on said outer data arc.
 11. The data arcs of claim 8 wherein:said step of disposing said servo data fields in an outer data arc withan offset is a step of disposing said servo data-field in said outerdata arc with said offset from said perpendicular adjacent data fieldlocated at said identical radial-angle position along a direction onsaid outer data arc toward a smaller radial angle projected from saidradial center perpendicularly to said servo data field of said innerdata arc.
 12. A method of disposing a plurality of substantiallyparallel data arcs on a flat data storage medium comprising: defining acentral perpendicular X-axis substantially perpendicular to saidparallel data arcs near a center point of said parallel data arcs;disposing at least two parallel-to-X-axis aligned servo-data fieldsrespectively in an inner data arc and an outer data arc with aninter-arc distance and disposing said servo data field on said outerdata arc with an offset on said outer data arc from a perpendicularadjacent data field located at an individual radial-angle positionprojected from a radial center disposed on said X-axis perpendicularlyto said servo data field of said inner data arc; and arranging saidoffset substantially proportional to said inter-arc distance andsubstantially proportional to SIN (θ) where θ is an angle a firstdirection projected from said radial center perpendicularly to saidservo data field disposed on said inner data arc and a second directionprojected from said radial center perpendicularly to said servo datafiled disposed on said outer data arc.
 13. The method of claim 12wherein: said step of disposing said servo data fields in an outer dataarc with an offset is a step of disposing said servo data-field in saidouter data arc at a location with said offset from a perpendicularadjacent data field located at said identical radial-angle positionalong a direction on said outer data arc toward a smaller radial angleprojected from said radial center perpendicularly to said servo datafield of said inner data arc.
 14. The method of claim 12 furthercomprising: dividing said parallel data arcs into multiple zones andassigning in each zone a reference inner arc; and disposing saidservo-data field on said outer data arc in each of said multiple zonesat a location with said offset on said outer data arc from aperpendicular adjacent data field located at said identical radial-angleposition along a direction on said outer data arc toward a smallerradial angle projected from said radial center perpendicularly to saidservo data field of said reference inner data arc.